CN1145339A - Normal sintered coal ash bricks - Google Patents

Abstract

A process for sintering ordinary powdered coal ash bricks is provided in which powdered coal ash (55-85), yellow sandy soil (10-40) and lime (4-5) is used as raw materials (wt.%) and includes the steps of mixing while wet-grinding powdered coal ash and yellow sandy soil, and then with lime cream, mixing with water, extruding the mixture to make soil strips, cutting the strip to form bricks, drying and sintering. Its advantages include low cost and high quality of bricks.

Description

Normal sintered coal ash bricks

The present invention relates to a kind of fired common brick and production technique thereof, be particularly suitable for the production of normal sintered coal ash bricks, belong to material of construction brick and tile burning techniques.

China is the country based on thermal power generation, and 200,000,000 kilowatts of present national installed capacitys then are 1.6 hundred million kilowatts by thermoelectricity 80%, if coal-fired average ash 25%, annual ash discharge amount is as many as 200,000,000 tons.A large amount of flyash are piled up as waste residue, land occupation, and contaminate environment causes public hazards, and this is a huge environmental protection and economic problems.

How flyash fully utilizes, and is the key subjects that power industry is very paid close attention to always, and all once dropped into a huge sum of money both at home and abroad and researched and developed, but still incomparable so far comparatively ideal terms of settlement.Utilizing flyash to produce building materials but is an effective way with flyash brick.China's application for a patent for invention number is 89109385.0 to disclose a kind of " free of calcining and steam curing flyash brick and preparation method thereof ", be to be raw material with flyash, cinder, lime, clay, after batch mixing, pressurization, moulding, the maintenance brick that gets product in air, but because intensity is low, cost height, use range are wide, and poor durability is not so be used widely.Another application for a patent for invention of China number is 92113185.2 to disclose a kind of " hypertonic powdered coal ash sintered products and production technique thereof ", be to be raw material with flyash and clay, through batch mixing, moulding, dry, SINTERING PRODUCTION standard square for building, perforated brick, fireproof insulation brick and wall floor tile etc., the present invention has improved the incorporation of flyash, the intensity of finished bricks also increases to some extent, but the intensity of dry body is difficult to reach the required requirement of strength of mass industrialized production in the production process, and the base substrate of producing is the economy brick of 100 * 100 * 15m/m and 200 * 100 * 60m/m, not as common brick is widely used.

The objective of the invention is to design a kind of is main raw material with flyash, compositing formula with addition of an amount of yellow sand and a small amount of lime, a kind of production technique of normal sintered coal ash bricks for building is provided, can not only improve the proportional quantity of flyash, can guarantee also that simultaneously industrial mass makes the intensity of dry body, and every technical feature of finished bricks all meets or exceeds the national standard of common building with brick.

Normal sintered coal ash bricks of the present invention, be to be main raw material with flyash, with addition of an amount of yellow sand (flour sand or lightweight mild clay or the two mixing) and a small amount of lime, its composition proportioning (weight %) is: flyash 55～85%, yellow sand 10～40%, lime 4～5%.Its best proportioning: flyash 75～82%, yellow sand 10～20%.Production technique is at first flyash and yellow sand to be put to roll stirring, then milk of lime is changed into milk of lime injection edge runner-wet mill and continue to roll stirring, add suitable quantity of water at last, thorough mixing, make compound breast water content be controlled to be 22～28%, compound is extruded into the mud bar through de-airing extruder, deliver to cutting adobe on the brick cutting machine by transmitting device, directly place on the drying cart with iron pallet, with and to go into kiln drying dry, dry body is gone into kiln and is controlled high temperature sintering by sintering curve, and the cooling kiln discharge promptly gets the normal sintered coal ash bricks finished product.

Below in conjunction with accompanying drawing the present invention is elaborated:

Accompanying drawing is technological process of production figure of the present invention.

As shown in drawings, at first flyash and yellow sand are placed by the proportioning weighing and roll pulverizing in the edge runner-wet mill. Lime-ash needn't sieve in the flyash, because lime-ash hardness is little, can roll pulverizing after entering to grind. Yellow sand is the mixture that flour sand, lightweight lam are let alone the one or both arbitrary proportion. Yellow sand is the glazing agent as high temperature sintering, and also any soil property of available laterite or black earth substitutes. Then lime being emulsified into milk of lime in emulsifier injects edge runner-wet mill and continues to roll and mix. Lime preferably carries out emulsification, also can directly not add the building stone ashes if there is the emulsification condition, and lime is as forming agent. Add at last suitable quantity of water, fully mix again, make the compound meeting water yield 22～28%. Compound enters vacuum. Mud extruder is squeezed into the mud bar. Because the flyash short texture, the space is big, and air content is many, adopts vacuum press can reduce residual air, increases mud bar intensity. The mud bar that mud extruder is extruded is delivered to cutting adobe on the brick cutting machine with reaching by chain or belt transmission. The wet green strength of flyash is little, can not manually move by a piece, needs put with iron pallet to place on the drying cart again, and it is dry directly to enter the kiln drying of tunnel type hermetically drying. Can utilize using residual heat from kiln furnace when dry, namely cause in the dry kiln with the high-temperature flue gas of air-introduced machine with calcining kiln, last low-temperature flue gas is emptying by chimney. Owing to select lime as forming agent, dry body strength can reach 1.6～2.0MPa, and available a dead lift and loading of kiln multilayer are piled up. Burn till and can finish in tunnel cave or annular kiln, when burning till, press sintering curve control high temperature sintering, its sintering curve is:

Normal temperature～500 ℃ are per hour heated up 80 ℃, heated up 6 hours,

500～800 ℃, per hour heat up～100 ℃, heated up～3 hours,

800～1100 ℃, per hour heat up～40 ℃, heated up～8 hours,

1100～1160 ℃, per hour heat up～10 ℃, heated up～6 hours,

1160 ℃ are incubated～6 hours,

1160～normal temperature opens the kiln naturally cooling or cooling is forced in air blast.

In high temperature burns till, yellow sand is as the wedding agent of the extremely low flyash of sintering degree, the yellow sand wedding agent that glazing shape maybe can be mixed in adobe during high temperature, the effect that while milk of lime at high temperature also still keeps forming agent, adobe still can keep certain intensity, do not produce fracture and distortion, treat firing temperature reduce to critical when following, the tangible firm fragment of brick of flyash brick formation section liquid phase.The cooling kiln discharge promptly gets the normal sintered coal ash bricks finished product.

Final product shows through quality examination department detected result: scum and lime blowing test are qualified fully, and every technical indicators such as anti-freezing property, strength grade and water-intake rate all meet or exceed national standard and require (specifically for details see attached table).

Advantage of the present invention and effect are:

(1) can utilize flyash in a large number, turn waste into wealth, turn harm into good, have bigger social benefit.

(2) adopt common yellow sand as the glazing agent, raw material is extensive, gathers materials on the spot, and does not destroy the arable land.

(3) adopt lime as forming agent, can increase blank strength, and have the good high-temperature sintering character.

(4) production technique is simple, and the equipment typing is optional, and raw material is inexpensive, and production cost is low, and good product quality has remarkable economic efficiency.

Embodiment 1:

Press flyash: yellow sand: the proportioning metering of lime=82: 14: 4, earlier flyash and yellow sand are mixed in edge runner-wet mill and roll pulverizing, then milk of lime is changed into milk of lime and inject edge runner-wet mill, continue to roll stirring, add water thorough mixing more in right amount at last, detect mixture moisture content 24%, be extruded into the mud bar through de-airing extruder, send brick cutting machine to cut base, get dry body substance 1.9kg, ultimate compression strength 1.6MPa, burnt brick size 240 * 115 * 53m/m after the drying, the heavy 1.84kg of monolithic brick, the other technologies index is listed in subordinate list.

Embodiment 2:

Press flyash: yellow sand: the proportioning metering of lime=75: 20: 5, processing condition be with embodiment 1, mixture moisture content 26%, dry back dry body substance 2.0kg, ultimate compression strength 2.0MPa, burnt brick size 240 * 115 * 53m/m, the heavy 1.9kg of monolithic brick, the other technologies index is listed in subordinate list.

The subordinate list normal sintered coal ash bricks

Sequence number	Test item	Technical requirement	Measured result
					Embodiment 1	Embodiment 2
			?1 ?2 ?3 ?4 ?4-1 ?4-2 ?5 ?5-1 ?5-2	Scum lime blowing anti-freezing property strength grade mean value R standard value f kWater-intake rate mean value monolithic maximum value			Not run-up powder, fall bits and decortication GB5101-91,5.6 bar a, b item monolithic dry weight loss≤2.0% MV7.5 〉=7.5PMa 〉=5.0PMa≤20%≤22%	Qualified 1.0% 7.5 7.8 7.0 9.5% 12.0%	Qualified 1.2% 7.5 8.1 7.7 9.2% 11.5%

Claims (5)

1. normal sintered coal ash bricks is to be raw material with flyash, yellow sand and lime, it is characterized in that proportioning raw materials (weight %) is: flyash 55～85%,

Yellow sand 10～40%,

Lime 4～5%.

2. normal sintered coal ash bricks according to claim 1 is characterized in that the best proportioning of flyash and yellow sand is respectively: 75～82% and 10～20%.

3. according to claim 1,2 described normal sintered coal ash bricks, it is characterized in that yellow sand is that flour sand, lightweight mild clay are let alone a kind of or the two is arbitrarily than falling to mix.

4. production technique that realizes above-mentioned normal sintered coal ash bricks, it comprises feedstock production, batch mixing, moulding, dry and burn till, it is characterized in that at first flyash and yellow sand placed to mix in the edge runner-wet mill rolling pulverizing, then milk of lime is changed into milk of lime and inject edge runner-wet mill, continue to roll stirring, add water thorough mixing more in right amount at last, make mixture moisture content be controlled to be 22～28%, compound is extruded into the mud bar through de-airing extruder, deliver to cutting adobe on the brick cutting machine by transmitting device, put on drying cart with iron pallet, with and to go into kiln drying dry, dry body is gone into kiln and is controlled high temperature sintering by sintering curve, the cooling kiln discharge brick that gets product.

5. production technique according to claim 4 is characterized in that sintering curve is:

Normal temperature～500 ℃ are per hour heated up 80 ℃, heated up 6 hours,

500～800 ℃, per hour heat up～100 ℃, heated up～3 hours,

800～1100 ℃, per hour heat up～40 ℃, heated up～8 hours,

1100～1160 ℃, per hour heat up～10 ℃, heated up～6 hours,

1160 ℃ are incubated～6 hours,

1160～normal temperature opens the kiln naturally cooling or cooling is forced in air blast.

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